1. Field of the Invention
The invention relates to an electrical test device, particularly to an electrical test device having isolation slot.
2. Description of the Related Art
Referring to FIG. 1, a conventional electrical test board 10 comprises a substrate 11 and a plurality of test pads 12. The substrate 11 has a first surface 111 and a second surface 112. The second surface 112 is corresponding to the first surface 111, and the second surface 112 is usually the back of the electrical test board 11. Each test pad 12 has a test hole 121 and an isolation slot 123. The isolation slot 123 is disposed on the periphery of the test hole 121, and defines a signal region 122. The signal region 122 is used for connecting to a signal terminal 151 of a test probe 15. The test hole 121 electrically connects to the signal region 122; therefore, the corresponding signal can be provided to the signal terminal 151 of the test probe 15.
The region outside the isolation slot 123 of the second surface 112 is a ground region, and the ground region is used for connecting a ground terminal 152 of the test probe 15. The isolation slot 123 is used to separate the signal region 122 and the ground region (i.e. the second surface 112) so that the signal region 122 and the ground region are isolated. The conventional electrical test board 10 must match with the test probe 15, and the test probe 15 is an expensive high frequency test probe. In addition, it is inconvenient to connect corresponding points for electrical test by using the conventional electrical test board 10 and the test probe 15.
Referring to FIG. 2, another conventional electrical test board 20 comprises a substrate 21 and a plurality of test pads 22. Similarly, each test pad 22 has a test hole 221, a signal region 222 and an isolation slot 223. The conventional electrical test board 20 further comprises a transmission line 24 and an auxiliary probe 25. The transmission line 24 is used for electrically connecting the signal region 222 and the auxiliary probe 25 so that the test probe 26 can receive the corresponding signal from the signal region 222 after connecting to the auxiliary probe 25.
However, actual test point (signal region 222) of the conventional test structure must further connect to the transmission line 24 and the auxiliary probe 25 for test so that the real electrical characteristics of the signal region 222 cannot be directly tested easily.
Consequently, there is an existing need for electrical test board to solve the above-mentioned problems.